Remotely operated seafloor coring and drilling method and system

ABSTRACT

Method and apparatus for emplacing a structure such as a casing, piling or core barrel into the floor of a body of water, hereafter referred to as sea floor. The structure is mounted on a towable and submersible vessel which includes a number of ballast tanks, and means are provided to selectively vary the ballast in certain ones of the tanks in a manner causing the vessel to have selectively controllable negative or positive buoyancy for descent or ascent, respectively, to or from the sea floor. A support device on the vessel is adapted to move the structure between a horizontal orientation for towing and descent and an upright position for drilling. after the vessel reaches the sea floor. The vessel descends with a positive metacenter to maintain the established orientation until it reaches the sea floor, after which it is anchored and leveled for commencing the drilling operation. The structure is advanced into the floor through increments of drilling strokes by means of rotating, through oscillatory or continuous rotary motion, a clamping mechanism which is engaged at incremental positions along the length of the structure. Means are provided to control the thrust force between the drilling end of the structure and the sea floor. An umbilical cable supplies power and control functions from a surface ship to the submerged vessel. Water under pressure is circulated through the interior volume of the structure to carry cuttings material away from the cutting end. Following completion of the drilling operation grout material is pumped into the void spaces between the structure and sea floor. The vessel is recovered for subsequent use by disengaging the clamping mechanism from the structure and blowing selective ones of the ballast tanks to cause the vessel to have positive buoyancy.

United States Patent [191 Well et al.

[ 1 June 24, 1975 I 1 REMOTELY OPERATED SEAFLOOR CORING AND DRILLINGMETHOD AND SYSTEM [76] Inventors: Dale E. Well, 3902 Lincolnshire St..

Pascagoula, Miss. 39567; Kenneth C. Marley, 1074 Valley Forge Dr.,Sunnyvale, Calif. 94087 [22] Filed: Dec. 26, 1972 [21] Appl. N0.:318,114

[52] U.S. CI. 175/6; 61/535; 61/46; 61/465; 173/152 [51] Int. Cl. E21137/12 [58] Field of Search 175/6, 170, 19, 471, 122, 175/162, 203;173/152, 163; 166/77, 78; 61/535 [56] References Cited UNITED STATESPATENTS 1,706,002 3/1929 Sipe 61/50 2,488,074 11/1949 Thornley 61/502,766,011 10/1956 Winder 173/163 X 3,054,285 9/1962 Roosen 175/19 X3,095,048 6/1963 ONeill et a1. 175/6 3,282,339 11/1966 Hasha 166/78 X3,438,452 4/1964 Bernard et a1... 175/6 3,442,339 5/1969 Williamson...175/6 3,491,842 l/l970 Delacour 175/171 X 3,595,322 7/1971 Reimann....173/163 X 3,666,026 5/1972 Allard 173/152 3,763,654 10/1973 Matsushita.61/535 3,779,322 12/1973 Stevens 175/171 FOREIGN PATENTS OR APPLICATIONS1,085,775 10/1967 United Kingdom 175/203 Primary Examiner-Frank L.Abbott Assistant Examiner-Richard E. Favreau 5 7 ABSTRACT Method andapparatus for emplacing a structure such as a casing, piling or corebarrel into the floor of a body of water, hereafter referred to as seafloor. The structure is mounted on a towable and submersible vesselwhich includes a number of ballast tanks, and means are provided toselectively vary the ballast in certain ones of the tanks in a mannercausing the vessel to have selectively controllable negative or positivebuoyancy for descent or ascent, respectively, to or from the sea floor.A support device on the vessel is adapted to move the structure betweena horizontal orientation for towing and descent and an upright positionfor drilling. after the vessel reaches the sea floor. The vesseldescends with a positive metacenter to maintain the establishedorientation until it reaches the sea floor, after which it is anchoredand leveled for commencing the drilling operation. The structure isadvanced into the floor through increments of drilling strokes by meansof rotating, through oscillatory or continuous rotary motion, a clampingmechanism which is engaged at incremental positions along the length ofthe structure. Means are provided to control the thrust force betweenthe drilling end of the structure and the sea floor. An umbilical cablesupplies power and control functions from a surface ship to thesubmerged vessel. Water under pressure is circulated through theinterior volume of the structure to carry cuttings material away fromthe cutting end. Following completion of the drilling operation groutmaterial is pumped into the void spaces between the structure and seafloor. The vessel is recovered for subsequent use by disengaging theclamping mechanism from the structure and blowing selective ones of theballast tanks to cause the vessel to have positive buoyancy.

3 Claims, 22 Drawing Figures SHEET PATENTEDJUN 24 ms PATENTED JUN 2 4I975 SHEET .l -'ig.lO.

PATENTEDJUN 24 I975 SHEET Fig.|5

PATENTEDJUN24 I975 3,891,037

SHEET 9 Fig.l6

Fig.1?

REMOTELY OPERATED SEAFLOOR CORING AND DRILLING METHOD AND SYSTEMBACKGROUND OF THE INVENTION This invention relates generally toprocedures and apparatus for embedding casing, piling or other similarstucture into the floor ofa body of water, and for taking large coresamples from the sea floor.

Civil engineering contractors have traditionally ad hered to workingoffshore with conventional and cumbersome surface equipment andtechniques. Previously, harbor development and offshore constructiondrilling projects have required the use large surface work barges, orsupport vessels to install pier foundations, anchor piling or terminalfootings. This surface equipment demands a high daily plant rental fee,requires a large crew, and is very expensive to mobilize. Othersignificant disadvantages include their vulnerability to surface weatherand wave forces as well as costly down time for general maintenance andrigging.

Working offshore can be much more economical and practical if theproblem is attacked from a submarine point of view. It is, therefore,recognized that one prime factor inherent in surface constructionoperations offshore which prevents these operations from comparing morefavorably with similar situations on land is motion. If the motioncaused by surface weather and wave forces is eliminated as a factor,then a dramatic reduction in equipment, manpower, and support servicescould be realized.

SUMMARY OF THE INVENTION It is a general object of the present inventionto provide a method and apparatus for emplacing a core barrel, casing,piling or other type of structure into the floor of a body of water.

Another object is to provide method and apparatus of the above characterfor civil engineering and underwater mineral exploration projects whichinclude the installation of pin pile anchor arrays for single pointmooring systems, the installation of foundation piles for fixedterminals, the utilization of various templates together with asubmersible drilling system for securing oil storage terminals,production platforms and other types of offshore structures withdrilled-in piles, and taking core samples from the floor of a body ofwater.

Another object of the invention is to provide method and apparatus ofthe above character in which a mobile submersible vessel carries acasing or other similar structure under controllable descent to aselected site on the sea floor where the structure is moved to adrilling position and the drilling operation is carried out under remotecontrol from a surface vessel, The method and apparatus described hereinthus makes it possilbe to complete the drilling operation without therequirement of surface drilling equipment and attendant sizeable workcrew, large barges, or support vessels,

Another object of the invention is to provide a method and apparatus ofthe above character in which a vessel carries a length of a casing orother similar structure in such a manner to facilitate towing of thevessel on the surface of the water, and the acheive a positionmetacenter for the vessel during descent so that a predeterminedorientation is maintained until setdown at the drilling site. At thedrilling site, means are actuated under remote control from the surfacevessel to control a series of functions which include leveling andanchoring the vessel with the floor, elevating the structure to thedesired drilling orientation, oscillating or continuously rotating thestructure, circulating a stream of fluid for removing cuttings material,controlling the rate of cutting by the control of bit thrust, drill bitspeed and circulating fluid pressure, placing grout material in thevoids between the structure and surrounding formation, and recoveringthe vessel by disengaging the same from the structure and creating acondition of positive buoyancy for ascent to the surface.

The method of the present invention employs a submersible vessel uponwhich is mounted a length of structure such as a casing, piling or corebarrel. The vessel is towed by a surface ship to a location on thesurface of the water above the desired drilling site after which waterballast is added to make the vessel negatively buoyant in a stableupright orientation for controlled descent to the drilling site.Following setdown at the site the vessel is leveled and anchored withthe floor and the casing or other structure is then elevated to thedesired drilling orientation. Water is pumped through the interiorvolume of the structure through a hose connected to the top of thestructure. Drilling functions such as drill bit pressure, peripheral bitcutting speed, water circulating pressure and the like are monitored andcontrolled by both automatic controls on the vessel and by automatic andmanual controls on the surface ship through leads extending along anumbilical cable. As drilling progresses and the structure advancethrough incremental strokes into the formation of the sea floor, theclamping mechanism is released and moved upwardly for re-engagement withthe structure for each subsequent stroke. After drilling is completedgrout material is pumped from the surface ship through a line along theumbilical cable to the void spaces between the structure and surroundingformation. After the grout material sets a pull test can be applied onthe emplaced structure by exerting a vertical force on the clampingmechanism, or by blowing water from the ballast tanks. The vessel isretrieved by releasing the clamping mechanism and blowing sufficientballast to create a positive buoyancy in the vessel for a controlledascent.

In the apparatus the vessel is constructed with main water ballast tanksand a plurality of pressure tanks positioned about the periphery of thevessel whereby the degree of buoyancy and vessel orientation duringdescent and ascent may be controlled. A support device is provided tosupport the structure lengthwise of the vessel for towing and descent.The support device is adapted to elevate the structure to an uprightdrilling position with the cutting end lowermost. A clamping devicereleasably engages the structure and either oscillatory or continuousrotary motion is imparted to the clamping device for drilling. Thevertical thrust force, and thereby bit pressure, is controlled byhydraulic actuators connected with the clamping device. Groundengaginglegs provided with helical blades are mounted about the periphery of thevessel for leveling and anchoring the vessel with the floor. A waterpump carried on the vessel pumps water into the interior volume of thestructure for removing cuttings material, and a three-way valve isprovided to direct grout material pumped from the. surface ship into theinterior volume for cementing the structure in place.

A method of pulling the vessel down to the sea floor under positivebuoyancy and then adding one or more hydraulic winches to the vessel andcontrolling these winches with separate hoses from the surface craft.

This method would include emplacing weights or anchors on the sea floorto which are attached cables connected to the winches on the vessel.

The vessels ballast tanks are flooded as previously discussed untilthere remains less positive buoyancy than the haul down capasity of thewinches and the negative weight of the anchors on the bottom. Thewinches are then acitvated to pull the vessel down to the sea floor.Once the vessel is on the sea floor the ballast tanks are completelyflooded to acheive the maximum gross weight on the bottom for commencingdrilling operations.

Additional objects and features of the invention will appear from thefollowing description in which the preferred embodiments have been setforth in detail in conjunction with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view ofapparatus for carrying out the method of the invention showing asubmersible vessel and exemplary casing structure in three sequentialmodes of operation.

FIG. 2 is a perspective view of an enlarged scale of the submersiblevessel of FIG. 1 showing the drilling mode thereof.

FIGS. 3A and 3B constitute a schematic diagram for the control system ofthe present invention.

FIG. 4 is a top plan view, partially cut away, of the vessel of FIG. 2with elements thereof removed for clarity.

FIG. 5 is an end elevational view on an enlarged scale along the line5-5 of FIG. 4 illustrating one groundengaging leg for the vessel.

FIG. 6 is a view similar to FIG. 5 illustrating another embodiment ofthe ground-engaging leg.

FIG. 7 is a partially broken away side elevational view of an enlargedscale of the cutting end of the casing structure shown in FIG. 2.

FIG. 8 is an end view taken along the line 8-8 of FIG. 7.

FIG. 9 is a side view similar to FIG. 7 illustrating another embodimentof the cutting end for the casing structure.

FIG. 10 is an end view taken along the line 10-10 of FIG. 9.

FIG. 11 is an axial section veiw on an enlarged scale taken along theline 11-11 of FIG. 10.

FIG. 12 is an elevational view on an enlarged scale taken along the line12-12 of FIG. 4 showing the clamping and rotary actuator, and verticalthrust mechanisms.

FIG. 13 is a lateral cross sectional view taken along the line 13-13 ofFIG. 12.

FIG. 14 is a partially broken away top plan view on an enlarged scaleshowing details of elements of the structure of FIG. 12.

FIG. 15 is a section view taken along the line 15-15.

FIG. 16 is a schematic diagram showing the circuit for directing fluidfor cuttings removal, and for directing grout material for cementing theillustrated casing.

FIG. 17 is partially broken away and side elevational view of anotherembodiment of the invention.

FIG. 18 is a partially broken away cross sectional view taken along theline 18-18 of FIG. 17.

FIG. 19 is a schematic diagram of the control circuit for the elementsshown in FIG. 17.

FIG. 20 is a partially broken away side elevational view of anotherembodiment of the invention.

FIG. 21 is a cross sectional view taken along the line 21-21 of FIG. 20.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1 there isshown at 20 apparatus for emplacing a structure such as an exemplarycasing 21 into the floor 22 ofa body of water such as a lake, river orocean. While the method and apparatus of the invention will be describedwith particular reference to emplacing such a casing for use as ananchor attachment or mooring in the sea floor, for example, it isunderstood that the invention will find broad application where othersimilar structures are to be emplaced, e.g., in drilling core barrelsfor offshore civil engineering studies and mineral exploration, and indrilling offshore piling for bridges, platforms, trestles and piers.

Apparatus 20 is adapted to be selectively buoyant or submersible underinfluence of an automatic and manual control system to be describedhereafter. Apparatus 20 defines a vessel which, in its buoyant mode, isadapted to be connected with a surface ship or craft 23 by tow cable 24and bridle 25 for transport over the surface of the water to a locationsubstantially above the desired drilling site on the sea floor. Casing21 is mounted on the vessel in a transport orientation extendinglengthwise of the vessel. For submersion and drilling operations anumbilical cable 26 is connected to the vessel to carry power and controlcircuit leads from the surface ship, craft or station. Prior to descent,two cable 26 is disconnected and the control circuit operated in amanner to be described causing the vessel to submerge toward the seafloor in the upright stable orientation illustrated at 20'. Followingsetdown on the sea floor, the vessel is caused to assume its drillingmode with casing 21 elevated, as illustrated at 20".

Referring to FIG. 2, apparatus 20 is illustrated in greater detail. Asupport frame 27 of welded channel member construction is provided toform an elongated support configuration. Ballast container means 28comprising a plurality of ballast and pressure tanks are secured to thesupport frame, and a pair of flat walkways or decks 29, 31 are mountedabove the tanks and extend lengthwise of the vessel. A false bowstructure 32 is secured to the forward end of the frame to facilitatetowing of the vessel over the surface of the water. Casing 21 is mountedadjacent its drilling end 33 to the support frame by a support anddrilling device 34 which is adapted to move the casing between ahorizontal transport position for transport and descent (illustrated inbroken-line at 21' in FIG. 2) and an upright drilling position shown insolid line. In the drilling position the longitudinal axis of the casingis disposed along a predetermined angle of entry with respect to the seafloor. The end 35 of the casing remote from the drilling end issupported in the horizontal transport position by a pair of semicircularsupport cradles 36, 37 mounted above the frame.

Referring to FIG. 4 details of the ballast container means areillustrated. A pair of elongated hollow ballast containers, preferablycylindrical in shape, comprising main ballast tanks 38, 39 are mountedto the frame with an orientation lengthwise of the vessel and positionedto straddle casing 21 in the latters transport position. A plurality oftransversely extending spacedapart baffles 41, 42 are mounted in theinterior volumes of the two main ballast tanks 38, 39 to obviate theeffects of ballast surge which could otherwise occur when the vesselundergoes pitching, rolling or yawing movement. Main tanks 38, 39are'flooded with a suitable ballast, preferably water, both when thevessel is on the surface and when submerged to contribute sufficientweight to establish a low center of gravity and maintain a stableupright orientation. The main ballast tanks are soft tanks, that isthese tanks are substantially completely flooded with water ballastwhile submerged and need not be designed to withstand extremehydrostatic pressure while submerged.

A pair of elongate hollow ballast containers 43, 44, preferablycylindrical in shape, are mounted on frame 27 outboard of main tanks38,39 and with an orientation lengthwise of the vessel. The containers43, 44 are hard pressure vessels constructed to withstand thehydrostatic pressures encountered at the maximum design working depth of660 feet. The containers are positioned about the periphery of thevessel to provide, by means of varying the amount of ballast, controlover both the vessels buoyance and its trim or stability during towing,descent and ascent. Each of the containers 43, 44 is provided with apair of internal diaphragms or bulkheads 46, 47 and 48, 49 definingthree pressure tanks on each side of the vessel. Thus, each container isdivided into a pair of stabilizer tanks 51, 52 positioned at oppositeends of a central variable tank 53. The control circuit of FIG. 3provides means to flood the two variable tanks 53 with water ballast forboth descent and drilling phases, and to blow these tanks withcompressed air for ascent of for a pull test. The control circuitfurther provides for independently flooding the four stability tanks 51,52 with variable amounts of water ballast to maintain'stability duringdescent and ascent, and to maintain trim for towing on the surface. Eachof the stability and variable tanks are further provided with aplurality of transversely extending axially spaced baffles 54, 55 whichfunction to obviate the effects of ballast surge when the vesselpitches, rolls or yaws. As shown in FIG. 2, a plurality of high pressuregas tanks 56 are mounted below the decks 29, 31 to supply a source ofcompressed air for blowing ballast from the main, variable and stabilitytanks.

Suitable fixed ballast weight means is provided to establish, incombination with the weight of the frame, casing, onboard equipment andballast in all tanks, an overall center of gravity which is disposedbelow the vessel's center of buoyancy. This fixed ballast meansincludes, in the illustrated embodiment as shown in FIG. 5,longitudinally extending heavy skegs 57 filled with a ballast such aslead and secured by suitable fastener means along the bottom surfaces ofeach of the Means are provided for leveling and anchoring the vesselwhen it is on the floor at the drilling site. This means includes aplurality of ground-engaging legs 61,62,63,64, each of which ispositioned adjacent a respective corner of the vessel. FIG. 5illustrates details of the typical leg 61 mounted aft on the vesselsport side below deck 31 and between main ballast tank 38 and stabilizingtank 52. This leg includes a shaft 66 carrying a helical blade or auger67 and a lowermost auger drill bit 68. The shaft extends upwardly fordriving engagment through a suitable spline connection or the like withan hydraulically powered rotary motor 69 mounted between the two tanks.The motor is in operating connection with a suitable linear actuatorsuch as the hydraulic cylinder 71. Actuation of the rotary motors andlinear actuators for the four legs by the control system followingsetdown drills the legs into the floor to anchor each corner of thevessel against the forces of currents, tides, umbilical drag, reactionforces from the drilling torque applied to the casing, and reactionforces of the thrust acting on the cutting end of the easing. Suitablesensors (not shown) are provided on the vessel to provide an indication,by remote signals through the umbilical to the surface ship, of thevessels orientation with respect to the horizontal. To bring the vesselto the desired orientation selected ones of the four linear actuators 71are energized to extend or retract respective legs and thereby raise orlower selected corners of the vessel. Following completion of thedrilling operation each of the rotary motors are reversely actuated toretract the augers from the floor.

FIG. 6 illustrates another embodiment for the ground-engaging legs ofthe invention. In this embodiment each of four leveling legs 72 includea length of pipe 73 provided at is lower end with a flat leveling pad74. Pipe 73 is adapted to be interchangeable with the auger shaft 66 ofthe embodiment of FIG. 5. The upper end of pipe 73 is operativelyconnected with linear actuator 71 to raise and lower a respective cornerof the vessel in a manner similar to that explained in connection withthe embodiment of FIG. 5. The embodiment of FIG. 6 especially adaptedfor leveling the vessel where sea floor conditions and drillingrequirements do not necessitate anchoring, and in such case it is notnecessary to actuate rotary motors 69.

Casing 21 is of cylindrical shell configuration and is of the selectedsize and wall thickness and material as determined by particularspecifications and requirements. As an example, the casing size may bein the range of 12 to 72 inches in diameter with l% inch wall thickness,and with casing length up to 50 feet. Where it is desired to drill atgreater length into the seafloor formation, then the inventionfacilitates the insertion of longer lengths of casing for deeperdrilling. The upper end 35 of the casing is closed by a circular cover76 secured by means such as welding. A padeye 77 may be welded to thetop surface of cover 76 for attachment of an anchor chain or the like bysuitable means such as a shackle where the emplaced casing is to be usedas an offshore mooring or anchor.

As shown in FIGS. 7 and 8, cutting end 33 of the casing includes asuitable bit shoe 78 of cylindrical configuration secured to the casingby suitable means such as welding. The distal end of the bit shoe isformed into a drag bit type cutter by mounting a plurality of hardfacebits 79 by suitable means such as welding about the bit shoe rim. Asbest illustrated in FIG. 8, the bits are staggered in orientation suchthat alternate ones of the bits incline radially inwardly and outwardlyfrom the casing. As cutting progresses the bits cut annular spaces orvoids 81, 82 (FIG. 16) into the seafloor formation on opposite sides ofthe casing wall. These annular spaces provide a path for circulation offluid for removing cuttings material, and for circulation and deposit ofgrout material where it is desired to cement the easing into theformation. In addition, because only a narrow, circular path is drilledinto the formation, horsepower and torque requirements are reduced ascompared to conventional open hole drilling where the entire diameter isdrilled out.

FIGS. 9-11 illustrate another embodiment of the invention in which amodified cutting end is provided on a casing 83. In this embodiment abit shoe 84 formed of a plurality of annular reinforcing members86,87,88 is secured by welding to the distal end of the casing. Aplurality of cone-shaped roller bits 89 are mounted in spaced-apartrelationship about the periphery of the bit shoe on suitable brackets 91for rotation about axes inclined with respect to lonitudinal axis of thecasing. The roller bits are dimensioned so that the inner and outer endfaces thereof radially project inwardly and outwardly of the walls ofbit shoe 84 so that, as cutting progresses, annular spaces or voids 92,93 are formed between the casing wall and surrounding seafloor formationfor circulation of cuttings removal fluid and grout material.

Support and drilling device 34, best shown in FIGS. 2,12, and 13,supports the casing adjacent its cutting end in the transport mode,elevates and lowers the easing to and from the drilling position, andsupports and inparts drilling motion to the casing in the drilling mode.The device 34 includes a pair of extensible actuators 94, 95, preferablyhydraulic rams, pivotally mounted at their head ends to frame 27 andpivotally mounted at their rod ends 96,97 to clevis brackets 98, 99carried on supports 100, 101 which in turn are secured to pivot yoke 103on diametrically opposed sides of the casing. A casing clamp assembly102 is mounted on the pivot yoke which in turn is pivotally mounted atits inboard end to support from 27. An annular guide bearing 104 ismounted lowermost on yoke 103 and is sized to rotatably and slidablereceive and position casing 21. Alternatively, an additional casingclamp assembly, not shown, similar in construction and operation to thatof easing clamp 102, may be provided at the location of an in place ofguide bearing 104 to provide additional torque and vertical control, asrequired, for drilling or coring operations, or such alternate clampingmechanism may be used alone as the prime rotary power source. Casingclamp 102 is supported uppermost on the yoke for releasable grippingengagment with the casing 21. Both guide bearing 104 and the casingclamp thereby provide two-point support for the casing so that it isstabilized, when in its drilling mode, at a predetermined angle of entrywith respect to the sea floor.

Further support for the casing both in its transport and drillingpositions is provided by a semi-cylindrical guide shoe or bearing 106mounted on an A-frame 107 which in turn is pivotally mounted at itslower base legs to frame 27. The A-frame and guide bearing 106 arebiased by suitable means such as springs to pivot to- 7 Ward an uprightposition, as illustrated in FIG. 2 where it supports the casing in itsdrilling position. The A- frame is pivoted downwardly with the bearinghorizontally aligned with support cradles 36, 37 when the casing is inits transport position. An additional semicylindrical guide shoe orbearing 108 is provided diametrically opposite bearing 106 in thedrilling position of the casing. This guide shoe is supported by an A-frame 109 which is pivotally mounted at is apex to the shoe and at itslower base to false bow structure 32. An extensible actuataor 111,preferably an hydraulic ram. is pivotally mounted at its head end to thebow structure and at its rod end to a cross member on A-frame 109.Extension and retraction of actuator 111 under influence of the controlsystem positions guide shoe 108 to the desired orientation with respectto the vessel which will establish a predetermined angle of entry fordrilling the easing into the sea floor.

Casing clamp 102, as best illustrated in FIGS. 12-15, comprises anannular collar defined by a pair of arcuate jaw members 112, 113pivotally mounted together at overlapping ends by hinge pin 114 and withradially outwardly extending arms 116, 117 formed at their diametricallyopposite ends. A series of clamping teeth 118, 119 are provided aboutthe inner periphery of each jaw member. These teeth preferably are ofthe type known in the art as tong dies. The collar is opened and closedby actuator means 121 for disengaging and engaging, respectively, theclamping teeth about casing 21. This actuator means includes areversable rotary motor 122, preferably an hydraulic motor, connectedwith an annular support 123 which in turn carries the hinge pin for thetwo jaw members. Motor 122 powers drive means comprising a drive shaft124 formed with two series of right and left hand threads disposed onopposite sides of a central spacer flange 126. Gimbaled nuts 127, 128are mounted within slots 129 formed in each of the jaw arms. The nuts127, 128 are in threadable connection with opposide threads of shaft124, and the nuts are pivotally carried on pins 130, 131 mounted withinarms 116, 117. Rotation of the drive shaft in either rotational sensemoves the nuts apart or together along the shaft and thereby causes thejaw members to open and close.

Means for imparting oscillatory rotary movement to the casing clampingand casing is provided at 132.

This means includes a circular gear track or ring gear 133 formed aboutthe outer periphery of annular support 123. The gear track is recessedwithin the support so that upper and lower annular rims 134, 135 on thesupport project radially outwardly of the track. A pair of sector gears137, 138 are mounted at diametrically opposite positions in drivingengagement with gear track 133. The upper and lower axial end faces ofeach of the sector gears are slidably fitted between the inner surfacesof the upper and lower support rims 134, 135 for transmitting thrustforces therebetween. Drive shafts 139, 140 coupled to the sector gearsextend downwardly in operable connection through rotary actuators 142,143 mounted for vertical sliding movement in slots formed on pivot yokesupports 100, 101. Rotary actuators 142, 143 preferrably comprisehydraulic rotary actuators operated under influence of the controlsystem-to oscillate respective drive shafts back and forth through apredetermined circular arc. The lower most ends of the hydraulic rotaryactuators are engaged with suitable linear actuators 147, 148 whichpreferably comprise hydraulic rams mounted on pivot yoke 103. The linearactuators are operated under influence of the control system to impartthrust forces to clamp 102 and casing 21 in either direction along thelongitudinal axis of the casing. Thus the actuators may be energized toexert a selectively variable thrust force away from the sea floor tounload a portion of the casing weight and thereby establish apredetermined axial thrust on the cutting bits for controlling thecutting rate, as monitored by the operator on the surface ship throughremote signal leads extending along the umbilical. As cutting progressesthe two actuators are caused to automatically retract permitting theclamp and casing to move downwardly through a cutting stroke on theorder of 4 feet, At the end of thisstroke clamp 102 is actuated fordisengagement from the casing and the actuators 147, 148 are then causedto extend and raise the disengaged clamp upwardly along the casing forre-engagement in a new clamping position for initiating the nextsuccessive cutting stroke. After the casing is drilled into theformation to the desired depth and any injected grout material has set,actuators 147, 148 may be energized to extend and apply a verticalthrust force to the casing with the clamp engaged for purposes ofperforming a pull test on the embedded casing.

The present invention also faciliates the drilling of casing, piling orcore barrels of various diameters through utilization of a single casingclamp and a plurality of paired semi-cylindrical adapter members, notshown, fitted with inwardly facing clamping teeth. The adapter memberswould be mounted about the inner circumference of the two jaw memberswhere it is desired to drill a smaller diameter casing. At the sametime, an adapter ring of the appropriate diameter would be mountedwithin guide bearing 104 for supporting the lower end of the casingstructure.

In the schematic of FIG. 16 there is shown a system for circulating ineither direct or reverse flow directions a fluid for cuttings materialremoval. The system further provides for the injection of a flowablegrout material where it is desired to cement the casing or otherstructure into the formation. A water pump 149 is mounted within asuitable protective enclosure 151 mounted on the submersible vessel andis driven by a suitable prime mover, preferably the electric motor 152,although other prime movers such as hydraulic or pneumatic motors mayalso be utilized. Electrical power to drive motor 152 is supplied fromthe surface ship by means of a cable extending along umbilical 26.During drilling, fordirect circulation of the fluid (as illustrated bythe arrows), pump 149 receives water from the sea surrounding the vesselthrough valve 54 and conduit 156 and discharges it under pressurethrough valve 157 and conduit 158 leading to a three-way valve 159. Thisthree-way valve directs the water through a branch conduit or flexiblehose 160 leading to an elbow fitting 161 which opens into the casingthrough casing cover 76. Sea water is thereby pumped into the interiorvolume 162 of the casing where it circulates downwardly along the voidspace of inner annulus 82 and discharges outwardly between the cuttingbits 79 to carry the cuttings material upwardly along the void space ofouter annulus 81 for deposit on the sea floor. Water pump pressure andvolume is controlled by automatic and manual controls as a meansofcontrolling both the rate of cuttings removal.

Depending upon veriables such as the type and hardness of the sea floorformation, as determined from predrilling coring or exploration surveys,the cuttings removal flow circuit may be set up for reverse flow duringthe drilling operation, e.g. where formation cave-in could otherwiseimpede direct flow. To establish the reverse flow circuit a branchconduit 163 and valve 164 are provided between conduit 158 and thedownstream side of valve 154, while a discharge conduit 167 and valve166 are connected with the outlet of pump 149 downstream of valve 157.The two valves 164, 166 which are both closed for direct flow operation,are opened for reverse flow with valves 154 and 157 then closed.Operation of pump 149 acts to draw sea water downwardly along annulus 81to carry cutting material from the bits upwardly along annulus 82 andthrough the casing into conduits 160, 158 and 163 for discharge into thesea through conduit 167.

While the schematic of FIG. 16 illustrtes the direct mounting of motor152 and water pump 149 on the vessel, the invention also contemplates asystem in which a water pump provided on the surface ship pumps thewater to the casing through a suitable flexible hose or conduitextending along umbilical 26.

Three-way valve 159 is adapted for actuation by suitable means such asthe hydraulic actuator 168 under influence of the control system todisconnect conduit 158 from branch conduit and connect the latter withgrout supply conduit 169 where it is desired to cement the casing inplace. A suitable grout material such as neat cement is then pumped fromthe surface ship into supply conduit 169 from a suitable flexible hoseextending along umbilical 26. The grout material is directed into branchconduit 160 into the interior volume of casing 21 where it circulatesdownwardly along annulus 82, outwardly between the cutting bits and upwardly into annulus 81 to fill the voids in the formation. The groutmaterial cures or sets after a time interval typically 4 hours afterwhich a pull test may be conducted either by applying a predetermineevertical thrust force on the casing with actuators 147, 148, by blowingthe ballast tanks with the casing clamp engaged, or by attaching a calbeor chain to padeye 77 and applying a pull force from a surface ship. Forreocvery of the vessel branch line 160 is disconnected from elbow 161 byremotely actuated means or by a diver.

FIGS. 17-19 illustrate another embodiment of the invention showing analternate system for applying drilling motion to an exemplary casingstructure 170. The casing is supported in its drilling mode with anorientation along the desired angle of entry by means of twosemi-cylindrical guide shoes 171, 172 Guide shoe 171 is pivotallymounted to support frame 173 by means of A-frame 174. This A-frame isbiased by suitable spring means to pivot in a counterclockwisedirection, as seen in FIG. 17. As the casing is brought to the drillingposition, the guide shoe 172 is pivotally mounted the support frame byan A-frame 176 which is moved to a selected position by means ofextensible hydraulic actuator 177 to establish the desired angle ofentry. The casing 21 is supported and positioned at its lower end bymeans of an annular guide bearing 181 together with a support anddrilling device 179 which is carried on a pivot yoke 182. As illustratedin the schematic of FIG. 19, pivot yoke 182 is mounted by suitable pinmeans 183 for pivotal movement on support frame 173. A pair ofextensible actuators, preferrably hydraulic rams, are pivotally mountedat their head ends to frame 173 and at their rod ends to support 188 onthe drilling device 179. Hydraulic fluid is directed through conduits186, 187 into the rams under the influence of the con trol system tomove the casing between its transport and drilling positions.

A rack and gear type oscillator motor 189 is carried by support 188which in turn is mounted for vertical movement above yoke 182 by meansof a pair of diametrically opposed linear actuators 191, whichpreferrably comprise hydraulic rams. Hydraulic fluid under pressure isdirected into the rams through conduits 192, 193 under influence of thecontrol system for controlling the thrust force on drilling device 179when the same is engaged with the casing to control bit pressure duringcutting, to move the casing back and forth for successive strokes, andto conduct the pull test after the casing is embedded in the formation.A casing clamp 194 similar to that described in connection with theembodiment of FIGS. 12-15 is mounted about the easing. This clampincludes a pair of arcuate jaw members 196, 197 pivotally mountedtogether at pin 198 and with a plurality of clamping teeth or tong diesmounted about their inner periphery. The jaw members are closed andopened to engage with and disengage from the casing by actuator meanscomprising a reversible rotary hydraulic motor 199 secured to theoscillator motor housing. Hydraulic fluid is supplied through flexibleconduits 201, 202 into the motor for turning threaded drive shaft 203 inthe selected direction for moving, through suitable gimbaled nuts, armson the two jaw members.

Oscillator motor 189 includes means forming a circular gear track orring gear 204 upon which casing clamp 194 is mounted. Diametricallyopposed sides of motor housing 206 are formed into a pair of hollowcylinders adapted to slidably received respective gear racks 207 each ofwhich is formed at opposite ends with a piston 208, 209 fitted withinand slidably mounted in the cylinders. The two gear racks tangentiallyengage gear track 204 which is oscillated through a predeterminedcircular are within an arc of up to substantially 90, although a backand forth oscillating arc of 35 is preferred. As shown in the schematicof FIG. 19 the racks are reciprocated by hydraulic fluid directedaltermatively through respective conduit pairs 211, 212 and 213, 214into opposite ends of the cylinder. As cutting progresses hydraulic rams191 are retracted through a cutting stroke on the order of four feet,after which clamp 194 is opened, rams 191 extended upwardly, and theclamp closed for re-engagement and initiation of the next successivecutting stroke.

FIGS. 20 and 21 illustrate another embodiment of the invention providinga modified form of the clamping mechanism specially adapted to providecontinuous rotary drilling motion to the exemplary casing 215. In thisembodiment a support and drilling device 216 is carried by a pivot yoke217 which in turn is mounted on the vessels frame in a manner similar tothat described in connection with the foregoing embodiments whereby thecasing may be pivoted between its transport and drilling positions. Anannular guide bearing 218 is mounted below the pivot yoke to rotatablysupport and position the lower end of the casing.

Support and drilling device 216 includes a casing clamp 218 having apair of arcuate jaw members 219,

220 pivotally mounted together at pin 222. A plurality of clamping teethor tong dies 223, 224 are mounted about the inner periphery of the jawmembers. A pair of arms 226, 227 are provided at the open ends of thejaw members, and a drive shaft 228 formed with two series of right andleft hand threads is in threadable connection with gimbaled nuts mountedwith in slots in the arms in a manner similar to that described inconnection with FIGS. 14 and 15. One end of the drive shaft is providedwith an enlarged socket head 229 formed with a recessed drive socket231. Clamp actuating means 232 is mounted on a bracket 233 connected bya suitable bracket 234 for conjoint movement with the casing clamplengthwise of the casing. This actuating means includes a drive member235 formed with a pointed end 236 having a configuration (e.g. square incross section) adapted to move into and out of driving engagement with acorresponding configuration for the recess of drive socket 231. Drivemember 235 projects through a reversable motor 237, preferably anhydraulic motor, and this hydraulic motor is mounted on a bracket 238which slides through a slot formed in bracket 233 lengthwise of thedrive member. The end of drive member 237 remote from end 236 isconnected with a suitable linear actuator 239, preferably an hydraulicram operated under influence of the control system. Extension andretraction of ram 239 reciporcates the drive member, together withhydraulic motor 237, so that pointed end 236 moves into and out ofengagement with drive socket 231. With the pointed end engaged in thedrive socket hydraulic motor 237 is actuated to turn the drive member inthe desired direction and thereby open and close the jaw members. Withthe pointed end retracted, the drive member clears the socketsufficiently to permit the jaw members and casing to undergo continuousrotary motion in either directional sense.

A gear track or ring gear 241 is formed between spaced rims 242, 243 ofannular support 244 upon which the casing clamp is mounted. This geartrack is recessed radially within the two rims and a pair ofdiametrically opposed pinion gear 246, 247 are mounted between the rimsin rotary driving engagement with the gear track. The pinion gears areadapted to transmit axial thrust forces to the casing clamp and easing.A pair of drive shafts 248, 249 extend downwardly from the two piniongears and are connected at their lower ends with suitable linearactuators 251, 252, preferably hydraulic rams, mounted to pivot yoke217. Suitable rotary actuators 253, 254, preferably hydraulic motors,are mounted in driving connection with the two shafts 248, 249, with thehousings for each motor mounted on brackets 256, 257 for slidingmovement in slots formed along upright frame members 258, 259 of thepivot yoke. Operation of the two rotary actuators 253, 254 underinfluence of the control system drives the pinion gears for turning theengaged clamp and casing, while at the same time the hydraulic pressurewithin the linear actuators 251, 252 is controlled to provide thedesired axial thrust force on the clamp, and thereby control bitpressure. As drilling progresses the rams are caused to retractdownwardly through a drilling stroke on the order of four feet, withrotary actuators 253, 254 and clamp actuating means 232 movingdownwardly with the drive shafts through the bracket and slot connectionon the frame members. As the extremity of each stroke is reached, therotary actuators are stopped with the jaw members and drive socketpositioned as shown in FIG. 21. Linear actuator 239 is then energized toextend drive member 235 until pointed end 236 is in driving engagementwith socket 231. Hydraulic motor 237 is then energized to turn the drivemember in a direction moving arms 226, 227 apart, thereby opening thejaw members for disengagement from the casing. Rams 251, 252 are thenextended to move clamp 216 together with clamp actuator 232, upwardlyalong the casing for a return stroke a distance on the order of 4 feet.Motor 237 is then energized to turn drive member 235 in a reversedirectional sense moving arms 226, 227 together so that the jaw membersreengage about the casing. Linear actuator 239'is then retracted todisengage the pointed end from the drive socket, and rotary actuators253, 254 are then energized to resume the drilling operation.

The casing, piling or core barrel structure may also be oscillated aboutits longitudinal axis for drilling by suitable structure, not shown, inwhich extensible hydraulic elevating and drilling rams of the type shownat 94 and 95 in FIG. 2 for moving the casing between its transport anddrilling positions are reicprocated in opposite directions. In such anarrangement the rod ends of these rams would be attached throughsuitable swivel connections for movement with the casing clamp. Axialthrust control rams of the type shown at 147, 148 in FIG. 12 would beconnected at their one end in annular slots formed around the casingclamp and at their other end with a yoke structure pivotally mounted tothe vessels frame. The control system in this arrangement would beeffective to direct hydraulic fluid to the elevating and drilling ramsin parallel connection for simultaneous extension and retraction toraise and lower the casing, and in series connection so that the samerams impart oscillatory drilling movement to the clamp, and thereby tothe casing.

FIGS. 3A and 3B schematically illustrate a preferred control system forthe invention. A suitable oil-filled enclosure 261 is mounted on thevessel to protect the component elements indicated as within theenclosure from sea water. A power cable 262 extending along theumbilical connects with a source of electrical power 263 on surface ship23 for operating electric motor 264 through lead 266, for operatingwater pump motor 152 (FIG. 16) through lead 153, and for operating leakdetector device 267 through lead 268. A control cable 269 carrying aplurality of signal leads for control functions to be hereafterdescribed also extends to enclosure 261 from the surface ship along theumbilical. While the operation of the various control and operatingelements will be explained as activated or controlled by hydraulic orpneumatic power, the invention contemplates that any suitable mediumcould be utilized for each function, such as electrical, hydraulic, orpneumatic media, or any combination thereof.

The electric motor 264 drives a suitable hydraulic power pump 271adapted to deliver approximately 30 GPM of fluid at 3,000 psi. Pump 271draws supply fluid through inlet 272 from the reservoir of hydraulicfluid or oil which fills enclosure 261. The pressurized fluid isdirected into a supply conduit 273 and branch conduit 274 to establish ahigh pressure circuit, and into a pressure reducer 276 which reduces thefluid pressure to substantially 500 psi for delivery into manifold 277to establish a low pressure circuit. A branch conduit 278 feeds into asuitable hydraulic accumulator tank 279 adapted to contain apressurizedsupply to fluid. An automatic control valve 281 provided in branchconduit 278 operates to direct fluid from the accumulator tank into thesupply conduit should pump operation fail or cease for any reason toinsure continued operation of the control elements for a number ofcycles. Alternatively, the hydraulic fluid for the high and low pressurecircuits may be supplied from suitable pumping equipment on the surfaceship connected with a flexible conduit inthe umbilical.

Low pressure manifold 277 feeds a plurality of solenoid-operatedhydraulic valves 282-290 which are actuated under remote control byelectrical signals received through the plurality of leads 292 containedin branch cables 293, 294. The branch cables extend into control cable269 and along the umbilical to suitable electrical signal generatingmeans incorporated into control console 296 on the surface ship. Branchcable 293 supplies leads to the five valves 282-286 controllingcirculation of fluid for cuttings removal and grout injection, and forflooding the ballast tanks. Branch cable 294 supplies the leads to thefour valves 287-290 controlling venting and blowing of the ballasttanks. The nine valves 282-292 direct return fluid into exhaust manifold295 which emptys into the interior of enclosure 261 through filter 296.Activation of the valves 282-290 under influence of electrical signalsreceived through their associated leads directs pressurized hydraulicfluid from manifold 277 into the associated pairs of conduits 297-305leading outwardly from enclosure 261 to the hydraulically activatedcontrol valves 159 and 308-315. Valve 282 is connected through theconduits 297 with the three-way valve 159 for selecting either direct orreverse water circulation for cuttings removal, or for grout materialinjection.

Valve 283 is connected through the conduits 298 with four flood valves308 (one of which is shown), with each valve 308 being mounted in alower portion of a respective one of the four stability tanks 51, 52.Upon activation of valve 283, the four flood valves are simulteneouslyopened for flooding the stability tanks.

Valve 284 is connected through the conduits 299 with flood valve 309which is mounted in a lower portion of the starboard variable ballasttank 53 for selective remote control flooding of this tank.

The valve 285 directs hydraulic fluid through conduits 300 into floodvalve 310 in the lower portion of the port ballast tank 53 for remotecontrol flooding of this tank.

The valve 286 directs hydraulic fluid through conduits 301 into fourflood valves 311 (one of which is shown) provided in the lower portionsof the main ballast tanks 38, 39 for remote control simultaneousflooding of these tanks.

Venting and blowing of the ballast tanks is accomplished in the controlcircuit by remote control of the four valves 287-290. Valve 287 directshydraulic fluid through conduits 302 into four vent-blow valves 312,(one valve is shown) each of which is mounted uppermost in a respectiveone of the four stability tanks 51, 52 for simultaneous venting of thecontained air for flooding, and for simultaneously blowing ballast fromthese tanks by establishing communication with a high pressure airmanifold 317 connected through high pressure valve 318 with the airsupply tanks 56.

Valve 288 directs fluid through conduits 303 into valve 313mounteduppermost on the starboard variable ballast tank 53 to vent thistank during flooding,

and to establish communication with high pressure air manifold 317 forblowing a selected amount of contained ballast for purposes ofmaintaining the vessels stability and trim.

Valve 289 directs fluid through conduits 304 into the valve 314 mounteduppermost on the port variable ballast tank 53 to vent this tank duringflooding, and to establish communication with high pressure air manifold317 for blowing a selected amount of ballast.

Valve 290 directs fluid through conduits 305 into two valves 315 (onevalve is shown), each of which is mounted uppermost in a respective oneof the main ballast tanks 38, 39 to either vent these tanks duringflooding, or to establish communication with the high pressure airmanifold for blowing selected amounts of ballast from the tanks.

A solenoid operated hydraulic valve 319 is provided to direct hydraulicfluid from low pressure manifold 277 into conduit 321 leading to anhydraulically operated main exhaust valve 322 which is adapted to ventair manifold 317, and thereby each of the tanks associated with thevalves 312-315. When one or more of the valves 312-315 is opened forventing, a signal is directed through lead 323 to energize valve 319 andopen this main exhaust valve thereby venting conduit 317 into the seathrough outlet 324.

A solenoid operated hydraulic valve 326 is provided to direct hydraulicfluid from low pressure manifold 277 through conduit 327 into the highpressure valve 318. Actuation of valve 326 by means of a signal receivedthrough lead 328 controls this high pressure valve to establishcommunication from the air supply tanks 56 into manifold 317 for blowingballast from the tanks associated with whichever of the valves 312-315are opened by the control system.

A pressure transducer 329 is provided in the low pressure manifoldconduit 277. This transducer senses fluid pressure in the conduit anddirects an electrical signal through lead 331 extending along branchcable 332 and the umbilical to a suitable indicator gauge on the surfaceship for purposes of monitoring the pressure level in the low pressurecircuit.

Conduit 274 in the high pressure circuit supplies fluid to solenoidoperated hydraulic valves 333-336 controlling leveling of the vessel.Selected ones of the valves 333-336 are energized by remote signalsthrough four leads 337 extending along branch cable 338 and theumbilical to the surface ship. Selective energization of the valve333-336 directs high pressure hydraulic fluid into conduit pairs 339-342for operating the hydraulic actuators 71 for raising and lowering thegroundengaging legs 61-64. Return fluid from the valves is directedthrough return conduits 343 into exhaust manifold 295.

The clamping and drilling functions are remotely controlled by means offour solenoid operated hydraulic valves 344-347 each of which isoperated under remote control by electrical signals supplied throughleads 348 extending along branch cable 338 and the umbilical to thesurface ship. Return fluid from the valves is directed through returnconduits 349 into the filter 296 for return to the reservoir.

Clamping motor 122 is activated for engaging and disengaging the clampwith the casing by means of valve 344. This valve directs supply fluidfrom high pressure manifold 274 into a pair of conduits 350 for forwardand reverse operation of the clamping motor. A flow control regulator351 is provided upstream of valve 344, and this regulator is adapted tobe manually set, either prior to descent or by diver assistance whilesubmerged, the desired flow rate, e.g. up to 10 GPM, for controlling theoperating speed of the clamping motor.

Valve 345 controls the pair of elevating rams 94, 95 to raise and lowerthe casing between its transport and drilling positions. Hydraulic fluidsupplied to this valve from high pressure manifold 274 is directed tothe rams in parallel connection through conduits 352. A flow regulator353 is provided in this branch conduit for manually setting, eitherprior to descent or by diver assistance while submerged, the fluid flowrate, e.g. up to 10 GPM, to the elevating rams for controlling the rateof easing elevation.

Valve 346 is provided to control the linear actuators 147, 148 which inturn control the axial thrust force on the clamp and casing, and providefor downward advance of the casing through its drilling stroke andupward movement through its return stroke. Hydraulic fluid is suppliedto the valve 346 from high pressure manifold 274, and the fluid isdirected to the actuators in parallel connection through a pair ofconduits 354. A remotely controled pressure regulator 356 is providedupstream of valve 346 to control the pressure of fluid supplied to thelinear actuators, and thereby control the thrust forces produced by theactuators. The regulator 356 is controlled by electrical signalsreceived through a lead 357 extending along branch cable 338 and theumbilical to the surface ship. A pressure transducer 358 is alsoprovided upstream of valve 346 to generate electrical signals throughlead 359 extending along branch cable 338 and the umbilical to asuitable indicated gauge on the surface ship for purposes of monitoringthe working pressure of the actuators. This permits the drillingoperator to calculate the axial thrust force on the casing to determineand control drilling bit forces, and thereby control drilling rate.Valve 347 controls the operation of the two casing oscillator rotarymotors 142, 143. Hydraulic fluid is supplied to this valve from highpressure manifold 274 and the fluid is directed to the motors inparallel connection through a pair of conduits 361 and an automatic flowreversing valve 362. A flow regulator 363 is provided upstream of valve347, and this regulator is remotely controlled by electrical signalsreceived through lead 364 extending along branch cable 338 and theumbilical. The drilling operator on the surface ship may thereby controlregulator 363 to establish the desired flow rate into the oscillator orrotary motors and thereby control the casing oscillating rate or rotaryspeed, perferrably up to a maximum of 10 cycles per minute or 20 rpmwhich inturn controls the peripheral cutting speed of the bits. The flowreversing valve 362 automatically reverses flow to the motors 142, 143responsive to these motors reaching opposite ends of their respectivestrokes. In the case of rotary motors the functions of 362 are notrequired. A pressure transducer 366 is provided in communication withhigh pressure manifold 274 to generate a remote electrical signalthrough lead 367 extending along branch cable 339 and the umbilical to asuitable pressure indicator on the surface ship.

Leak detector 267 is provided within enclosure 261 to provide a remotealarm signal indicating any salt water leakage into the enclosure. Asuitable open circuit switch 339 is provided and is adapted to short outresponsive to the leakage of sea water into the enclosure and close acircuit through lead 341 extending along the umbilical to the surfaceship.

An example of the use and operation of the invention is as follows. Asubmersible vessel is constructed in accordance with the embodiment ofFIGS. l-S, 12-16. It will be assumed that a casing having a drilling endconstructed in accordance with FIGS. 7, 8 is to be embedded into the seafloor. The diameter, length and wall thickness of the casing is selecteddepending upon the desired application, e.g. as an offshore mooringattachment, and upon the type of formation material as determined fromstudies of geological core samples taken at the drilling site. In thisexample a casing size 4 diame- .ter 50' length and l /2 inches wallthickness is selected.

All ballast tanks on the vessel are blown until the desired drim isattained for stability while afloat. The tow cable 24 is attached andthe vessel is towed by surface ship 23 to a location above the drillingsite. The casing is loaded at this time from an adjacent barge or shipwith the casing cutting end supported by support and drilling device 34and with its opposite end supported by the two cradles 36, 37. Umbilical26 with its control and power leads and cables is them connected withthe vessel and the two cable may be detached. The stability tanks arefirst flooded to achieve the desired trim. The control circuit isactivated to initiate flooding of the main ballast tanks 38, 39 untilthey are substantially full. The control circuit is them activated tocontrol the flooding of variable tanks 53. Variable flooding into thetanks continues until just after a conditon of negative buoyancy isachieved. At this point the flooding and vent valves for all tanks areclosed and the vessel begins its descent. The vessels level orientationduring descent is maintained by monitoring suitable level indicators anda depth guage carried on the vessel, with controlled adjustments beingmade in the ballast as required. The vessel may be guided to thedrilling site either by free descent, or by the use of small anchors ortemplates placed on the sea floor with guide lines running to a surfacebuoy through a suitable bridle on the vessel. Descent is controlled at arate preferably within the range of 25-30 f.p.m. through remote controlfrom the surface ship by varying the ballast in the variable andstabilizer tanks. After the vessel achieves setdown at the drillingsite, the control circuit is activated to flood all tanks completely toestablish a maximum vessel weight on the seafloor for stability duringdrilling. The control circuit is then activated either by the surfacedriller or by diver attending the vessel to anchor it into the seafloorfor the drilling operation. The rotary motors 69 and linear actuator 71are energized to drill the ground engaging legs 61-64 into the seafloor. A determination is then made from observation of signals from thelevel indicators carried on the vessel as to whether adjustment isrequired to bring the vessel into the desired level orientation for thedrilling operation. lf so, selected ones of the linear actuators 71 areenergized to raise or lower corresponding corners of the vessel to bringthe vessel to the desired orientation. The casing 21 is then elevated tothe desired drilling position with its longitudinal axis disposed at apredetermined angle of entry with respect to the sea floor, e.g. aperpendicular angle of entry where the casing is to be used as a mooringattachment. To accomplish this, the control system is operated to firstactivate ram 111 and pivot guide shoe 108 to the orientation rewaterpump 149 and pump sea water into interior cavity 162 of the casing.Alternatively, a stream of air may be injected into the stream ofcirculating water so that an air-water mixture is created to assist inlifting the cuttings from about the drill bits. Casing clamp 102 islocked in engagement about the casing and oscillator motors 142, 143 areactivated by the control circuit to commence oscillation through anangle of 35 at a rate of thirty oscillations per minute by imparting600,000 foot pounds of torque from the oscillating motors. At the sametime, linear actuators 147, 148 are operated by the control circuit toestablish a pre-determined axial thrust force on the clamp, e.g. 157tons of thrust force, to maintain the desired bit thrust force. Rotarydrilling speed is initially calculated from bottom conditions such astype and hardness of formation, and overburden, and the like. Asdrilling progresses the surface driller or attending diver monitors thecontrol gauges and indicators signalling bit thrust force as a functionof axial thrust, cutting bit speed as a function of oscillating rate,and water pressure within the casing as a function of discharge pressurefrom pump 149. As the casing penetrates different formations, thecontrol circuit is activated to adjust the bit thrust force, drillingspeed and pump pressure to maintain the desired drilling rate.Furthermore, the control system automatically retracts the linearactuators 147, 148 through the cutting stroke by maintaining therequired fluid pressure into these actuators.

After the casing moves to the end of its 4 foot cutting strokeoscillator motors 142, 143 are stopped and clamp actuator 122 energizedto disengage jaw members 112, 113 from the casing. Linear actuators 147,148 are then energized to extend and raise casing clamp 102 for a 4 footreturn stroke, afterwhich clamp actuator 122 is reversed to re-engagethe jaw members about the casing. The foregoing drilling steps are thenrepeated for a successive number of strokes until the casing is drilledto the desired depth into the formation. The drilling operator monitorsthe drilling depth by counting the number of drilling strokes.

After the desired drilling depth is reached, oscillator motors 142, 143and linear actuators 147, 148 are deenergized. Water circulation iscontinued for a number of minutes after drilling ceases to flush cleanthe annuli 81, 82 surrounding the casing. Three-way valve 159 is thenactuated into its grout circulation mode and a suitable grout materialsuch as neat cement is pumped from the surface ship along supply line169 into the interior volume of the casing for deposit in the voidsbetween the casing and formation. After grout injection is completedline 169 is disconnected by a diver.

Following injection of the grout material, the vessel 20 may either beimmediately returned to the surface or utilized to perform a pull teston the emplaced casing. For immediate return, the control system isoperated to disengage casing clamp 102 from the casing and back-off,through reverse rotation of motors 69 and re-

1. An apparatus for emplacing a core barrel, casing, piling or othertype of structure having one end thereof adapted for cutting material inthe floor of a body of water, including the combination of a supportframe, ballast container means on the support frame, means to introduceballast into said container means to create negative bouyancy for saidapparatus, means to remove ballast from said container means tocreat-positive buoyancy for said apparatus, means on the frame tosupport a length of said structure for movement to a position with itslongitudinal axis oriented along a predetermined angle of entry withrespect to said floor and with said cutting end disposed lowermost, andmeans to move said one end of the structure to cause the structure tocut into and advance toward said floor along said angle of entry, meansto cause said core barrel, casing, piling or other type of structure ofoscillate about its longitudinal axis through a pre-determined arc, saidmeans to include a combination of clamping means to releasably engagethe outer periphery of said core barrel, casing, piling or other type ofstructure, means to impart rotary motion to said clamping means when thelatter is in clamping engagement with said core barrel, casing, piling,or other type of structure, means to oscillate said clamping means, corebarrel, casing, piling or other type of structure through apre-determined arc about the latters longitudinal axis to include meansforming a gear track on said clamping means with said gear trackextended about the longitudinal axis of said core barrel, casing, pilingor other type structure and means to drivingly engage said gear trackwith one or more sector gears engaging said gear track and means tooscillate said sector gears through a pre-determined arc and impartrotary motion to said gear track, said clamping means, said core barrel,casing, piling or other type of structure.
 2. Apparatus as in claim 1 inwhich said clamping means includes a collar mounted about saidstructure, gripping means on the inner periphery of said collar forreleasably engaging said structure, said collar being adapted to moveradially to and from said structure to respectively cause said grippingmeans to grip with or release from said structure, drivable meansmounted with said collar to cause said collar to undergo said radialmovement, and actuating means mounted with said frame and including adrive member engageable with said drivable means to actuate the latterwhen said means to rotate said structure is inactivated, and means tomove said drive member into engagement with said drivable means forgripping or release of said gripping means, or out of said engagementwhereby said clamping means is free for rotation in a given angulardirection.
 3. Apparatus as in claim 2 in which said collar comprises atleast a pair of jaw members, means pivotally connecting one end oF eachjaw member together, and said means to open and close the collarincludes a drive shaft, means forming two series of threads on the shaftwith opposite rotational senses, means threadably connecting said twoseries of threads with respective portions of said jaw members on endsthereof opposite said one end, and means to turn said drive shaftwhereby said collar is opened and closed.